This invention relates to a method for setting and managing printing conditions in a photographic printing exposure process.
It is generally necessary to properly manage the development of film negatives, the conditions of a photographic printer (referred to simply as "printer conditions" hereinafter), and the development of photographic papers in order to obtain high quality color prints quality.
In these days, with a conventional photographic printing device, the printer conditions are adjusted so that the photographic printing procedure is performed so as to exhibit a constant density value using a standard film negative (i.e. a film negative provided with an average density value of users). The preparation of the standard film negative, however, involves a troublesome work for manufacturing it, and moreover, since the standard film negative is usually developed in a standardized manner and the film negative thus developed is forwarded to a development laboratory, the preparation of the standard film negative is done without any consideration of the actual film negative characteristics and the differences of the developing treatment in the development laboratory. Namely, the standard film negatives are usually prepared without any consideration of the difference in regions such as snow regions, hot southern regions and the like or of the difference in seasons, i.e. spring, summer, autumn and winter. In addition, no consideration has been paid to the fading and the uneveness of color of the standard film negative itself, and it is thus impossible to easily set or manage the most proper printing condition in the respective development laboratory. Futhermore, as far as the standard film negative is utilized, procedures for setting and managing the printer conditions are manually performed. Such manual procedures are often likely neglected and also often obtain undesirable prints under the insufficient conditions of the photographic printer.
In another aspect, the exposing conditions of the standard film negative are set by exposing, printing and photo-measuring the standard film negative and repeating these procedures several times until the density thereof reaches the predetermined value. The correction or modification of the exposing conditions is generally carried out by exposing in the photographic printer due to the operation for adjusting stepwisely the density correction key or color correction key with respect to the actually used exposing conditions and for changing the amount of correction or types thereof. In this manner, the corrected amount of exposure needed to obtain the desired density is obtained by solving an interpolation equation or simultaneous equations in accordance with the obtained varied amounts of the density and the amount of exposure.
With the method for obtaining the correction amount of exposure described above, however, procedures or operations for inserting a standard original film, inputting the correction key, measuring the density and inputting the measured result are to be carried out or performed manually, so that these manual operations are often inadequately managed and insufficiently done. In addition, there are a lot of combinations of the correction keys for inputting the data and the correction precision will be increased as the amount of data increases, but on the other hand, labors and troublesome works will be increased for the measuring and the inputting processes. Furthermore, the relationship of the amount of exposure and the density of a material to be recorded is limited in a linear area, so that when the obtained value is greatly offset from the desired value, the setting of the initial exposure condition must be repeated several times so as to gradually approach the desired value. This includes problems on the measuring precision and the time required therefor. U.S. Pat. No. 4,464,045 corresponding to Japanese Patent Laid-open No. 127581/1980 is known as an improved method for the aforementioned defects. The method uses a plurality of gray steps and exposes on a recording material by using a calibrating original, thereby enabling one or more exposures without exposing in combination with the operation of the density correction keys or color correction keys, and further to inspect a larger area for the relationship of the amount of exposure vs density including a curve area of the recording material characteristics. However, since this method uses a calibrating original, the relationship of the amount of exposure vs the density becomes equivalent to the relationship of the calibrating original density vs the copy density. Therefore, it needs the calibrating original for respective types of film negatives. The method requires a number of additional procedures such as the manufacturing and supplying of the calibrating original, storage and managing of the operator, positioning to an exposure position at an operating time and the measuring of a number of printed density steps. In order to obtain the relationship of the calibrating original density with respect to the copy density, a mixed three-color light source or a white light source is usually used, and thus, the obtained density is represented by the density value formed with three color dyes of cyan (C), magenta (M) and yellow (Y). Accordingly, for instance, regarding the R (red) density, care should be taken for not only for the cyan C dye but also the R density components of the M and Y dyes. Moreover, in the conventional technique, the density variation amount obtained by changing the respective color light amounts of the respective color lights of red (R), green (G) and blue (B), with the density described directly hereabove being the standard thereof, is deemed to merely be the density difference. In other words, it is well known that the additive property of the density is not established with respect to the reflection density, and in spite of this fact, however, no consideration thereof is paid at all in the conventional method. Consequently, the accuracy is not sufficient in the determination of the amount of exposure, and it is generally difficult to accurately set or manage the conditions described above, such as the sufficient exposure condition, since the conditions are manually performed. It has been desired to develop a method which is accurately capable of setting and managing the conditions without manual procedures.